<!--
  多图上传组件
-->

<template>
    <el-upload v-model:file-list="fileList" list-type="picture-card" :before-upload="handleBeforeUpload"
        :http-request="handleUpload" :on-remove="handleRemove" :on-preview="previewImg" :limit="props.limit">
        <i-ep-plus />
    </el-upload>

    <el-dialog v-model="dialogVisible">
        <img w-full :src="previewImgUrl" alt="Preview Image" />
    </el-dialog>
</template>

<script setup lang="ts">
    import {
        UploadRawFile,
        UploadRequestOptions,
        UploadUserFile,
        UploadFile,
        UploadProps
    } from 'element-plus';
    import { uploadFileApi, deleteFileApi } from '@/api/file';

    const emit = defineEmits(['update:modelValue']);

    const props = defineProps({
        /**
         * 文件路径集合
         */
        modelValue: {
            type: Array < string >,
            default: [] as Array<string>
        },
        /**
         * 文件上传数量限制
         */
        limit: {
            type: Number,
            default: 5
        }
    });

    const previewImgUrl = ref('');
    const dialogVisible = ref(false);

    const fileList = ref([] as UploadUserFile[]);
    watch(
        () => props.modelValue,
        (newVal: string[]) => {
            const filePaths = fileList.value.map(file => file.url);
            // 监听modelValue文件集合值未变化时，跳过赋值
            if (
                filePaths.length > 0 &&
                filePaths.length === newVal.length &&
                filePaths.every(x => newVal.some(y => y === x)) &&
                newVal.every(y => filePaths.some(x => x === y))
            ) {
                return;
            }

            fileList.value = newVal.map(filePath => {
                return { url: filePath } as UploadUserFile;
            });
        },
        { immediate: true }
    );

    /**
     * 自定义图片上传
     *
     * @param params
     */
    async function handleUpload(options: UploadRequestOptions): Promise<any> {
        // 上传API调用
        const { data: fileInfo } = await uploadFileApi(options.file);

        // 上传成功需手动替换文件路径为远程URL，否则图片地址为预览地址 blob:http://
        const fileIndex = fileList.value.findIndex(
            file => file.uid == (options.file as any).uid
        );

        fileList.value.splice(fileIndex, 1, {
            name: fileInfo.name,
            url: fileInfo.url
        } as UploadUserFile);

        emit(
            'update:modelValue',
            fileList.value.map(file => file.url)
        );
    }

    /**
     * 删除图片
     */
    function handleRemove(removeFile: UploadFile) {
        const filePath = removeFile.url;

        if (filePath) {
            deleteFileApi(filePath).then(() => {
                // 删除成功回调
                emit(
                    'update:modelValue',
                    fileList.value.map(file => file.url)
                );
            });
        }
    }

    /**
     * 限制用户上传文件的格式和大小
     */
    function handleBeforeUpload(file: UploadRawFile) {
        if (file.size > 2 * 1048 * 1048) {
            ElMessage.warning('上传图片不能大于2M');
            return false;
        }
        return true;
    }

    /**
     * 预览图片
     */
    const previewImg: UploadProps['onPreview'] = uploadFile => {
        previewImgUrl.value = uploadFile.url!;
        dialogVisible.value = true;
    };
</script>